Hellenstein Castle Knights' Hall is the main festival venue of the Heidenheim Opera Festival.

The medieval ruins of the Knights' Hall at Hellenstein Castle is the breathtaking backdrop for the Heidenheim Opera Festival - and has been for 50 years! The castle is the first thing that catches the eye of everyone who comes to Heidenheim. No matter from which direction - the castle is visible from afar. The city's landmark sits enthroned like a protector at a height of 74 meters on the Hellenstein rock. The original Stauferburg was built between 1130 and 1145, but was almost completely destroyed in a fire in 1530. Only the ruins of the so-called Knights' Hall remain. Duke Friedrich I of Württemberg had a Renaissance palace built in front of this medieval building complex. A fortress with mighty rondelles and bastions arose. In the 18th century the complex fell into disrepair,
 
The fruit box of the castle now houses the museum for carriages, chaises and carts. The history of southwest German land transport is impressively documented here on four floors. 80 vehicles - from simple carts to magnificent baroque sleighs - give an insight into the means of transport from the 18th to the 20th century. The exhibits also include the oldest taxi in Germany, dating back to 1898. The Hellenstein Castle Museum is also located on the grounds of the castle and is divided into several areas. One section illuminates the prehistory and early history of Heidenheim, another the city history of the 19th and 20th centuries. In addition, the exhibition "Old Toys" as well as the "Indian Collection" and the Thea Voith Collection are presented.
 
A visit to the castle is also worthwhile for those who are less interested in history - if only because of the picturesque view over Heidenheim and its surroundings. Several ascents lead from the old town up to the Hellenstein. Of course you can also go by car. Hellenstein Castle is surrounded by a spacious, gently rolling park with old trees. This is followed by a 30-hectare wildlife park - a relaxing spot of forest in the middle of the city.
 
The first castle was built on Hellenstein at the beginning of the 12th century. Numerous Staufer humpbacks can be found in the walls of the castle ruins. In 1530 a major fire destroyed the castle. During the reconstruction in the middle of the 16th century, the castle was given the form that is recognizable today. Hellenstein Castle was built between 1595 and 1611 to the east of the castle. Today the Hellenstein Castle Museum is located in the Castle Church, Obervogtei, Burgvogtei and Altanenbau, and the Marstall, which is used for cultural events, is on the ground floor of the Burgvogtei. The way to the city leads into the artistically designed three-aisled hall of the north gate. The striking building on the southeast side, the fruit box, was built around the middle of the 15th century and served as a collection point for taxes in kind.

Today the museum for carriages, chaises and carts is housed there. From the southeast bastion, the Zwetschgengärtle, you can enjoy a wide view of the city and the surrounding area. To the west of the fruit box is the fountain garden with the 78 m deep Kindles fountain. The walk through the castle park leads through the north-east gate in the direction of Michaelskirche. The neighboring evangelical vicarage dates from 1771.